Dye Removal from Denim Textile Wastewater by a Combinative Adsorption and Regeneration System
Overview
This project adopts an integrative approach to remove indigo dye from textile wastewater. It combines the process of dye adsorption and adsorbent regeneration.
Research completion
2023
Commercialisation opportunities
Technology licensing
Problem addressed
Indigo dye plays a significant role in denim production but its use in denim production can have environmental implications. Wastewater generated during denim fabric dyeing can pollute water if not properly treated. This combinative process improves water quality and reduces adsorbent solid waste and cost, making it an environmental-friendly and cost-effective indigo dye treatment method.
Innovation
- The system uses alumina-based adsorbents as efficient dye adsorbent materials. Once the adsorbent material is saturated, it is regenerated through ozonation for reuse. It is an innovative, combinative and efficient dye removal system that achieves over 90% removal efficiency.
Key impact
- It improves water quality through decolourisation (colourity <25 pcu and Chemical Oxygen Demand (COD) <25 mg/L according to standard FZ/T 01107-2011).
- It reduces solid waste as the adsorbent has long service life of over 60 hours and it is highly reusable. After 10 processing cycles, the adsorbent remains over 90% removal efficiency for reuse.
- It is cost-competitive (USD 1.6/m3) compared with other conventional indigo dye treatment techniques (USD 1.6-6.2/m3), such as activated carbon
Award
- 49th International Exhibition of Inventions of Geneva (2024) - Gold Medal
Application
- Dye removal and wastewater treatment technology for denim production and other processes that generate dyed effluent.
Patent
- 18/457,123 (US)
- PCT/IB2023/058860 (PCT)
The Hong Kong Research Institute of Textiles and Apparel (HKRITA)
Established in 2006, The Hong Kong Research Institute of Textiles and Apparel (HKRITA) is funded by the Innovation and Technology Commission of the HKSAR government, and hosted by The Hong Kong Polytechnic University.
HKRITA has achieved research deliverables over the years around our research clusters targeting in sustainability, industry advancement and social benefits through our centre-owned research teams and laboratories as well as collaborations with industry partners and institutions.
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